As some of you know, I was asking around in the Fuji forums about a replacement for my ageing 6900zoom. While reading reviews on some prospective replacements, I noticed some conflicting information on the speeds of the Autofocus on some cameras. So basically, although I probably will end up learning to manual focus over time, I was wondering if there was any information for timings on the speeds of the AF system, specifically for the entry level offerings like the Canon EOS 400D/Digital Rebel XTi and the Sony A100. Preferably for normal usage situtations but I guess any info will do.

I have the Canon 400D and the AF is always fast enough for me which ever lens I use, I take shots of trains travelling at 100mph + in sports mode (continuous shooting) and with the very odd exception all are in focus. So think the 400D will suit you just fine, on the plus side IS is done in the lens and not the body so you will see the result in the view finder there and then not later when the picture is taken.

Hi Dean, the AF speed can vary considerably depending on the lens. Some premium models can be supremely quick, while cheaper kit lenses can seem quite laborious in comparison.

Personally speaking though it only becomes an issue when the subject is either moving quickly, or more importantly only in the frame for a very short period. Wildlife is a key example, especially a twitchy bird which might only stand still for a couple of seconds.

If you're shooting landscapes or portraits (in non pro situations), most DSLR lenses will be more than adequate and even the slow ones are normally a big step up from most non-DSLRs. The trick is to try a DSLR and proposed lens for yourself and see / feel how quickly it performs. Note if you are interested in manual focusing though, you'll become frustrated by the operation of most kit lenses as you tend to have to grip a thin ring at the end of the barrel. If you're into manual focusing, you'd want to upgrade from most kit lenses.

Roy's is an interesting example though - trains do move very quickly, but unlike, say, a footballer running towards you, a train's path should be very predictable along its tracks. Roy, do you find your AF system successfully tracks the train coming towards you and keeps it in focus at all times? It's a good test...

Roy's is an interesting example though - trains do move very quickly, but unlike, say, a footballer running towards you, a train's path should be very predictable along its tracks. Roy, do you find your AF system successfully tracks the train coming towards you and keeps it in focus at all times? It's a good test...

Gordon

Yes, I find that the AF system keeps the train in focus I usually set the camera on Sports Mode with continuous shooting and do a 20 - 25 frame burst and they are all in focus, have only had a couple that have not been in focus, but put that down to me moving right at the end to see if I could catch the number of the train before it disappeared in the distance.

OK thanks for the help. Just wondering. My old camera, which may or may not get replaced depending on what happens, has a slow AF. To give you an idea, I was at an event where people paraded around in costume in a similar vein to a fashion catwalk. Even though they were walking pretty slowly, the AF had a hard time getting a lock and eventually I just gave up taking pictures at that event...